View source for St. Peter Sandstone

{{Infobox rockunit
| name           = St. Peter Sandstone
| image          = St Peters Sandstone Pacific MO 5-med.jpg
| caption        = Old mine entrances in the St. Peter Sandstone formation in Pacific, Missouri, where it is still actively quarried nearby.
| type           = [[Formation (stratigraphy)|Formation]]
| age            = [[Middle Ordovician]]
| period         = Middle Ordovician
| prilithology   =
| otherlithology =
| namedfor       = St. Peters River (now Minnesota River), Minnesota<ref>{{cite journal|last1=Owen|first1=David|title=Preliminary report containing oulines of the progress of the geological survey of Wisconsin and Iowa, up to October 11, 1847|journal=U.S. 30th Congress, 1st Session, Senate Executive Document Serial Set|date=1847|volume=504|issue=2|pages=169, 170}}</ref>
| namedby        = [[David Dale Owen]]
| region         = [[Midwest]]
| country        = [[United States]]
| coordinates    =
| unitof         = [[Ancell Group]]
| subunits       =
| underlies      = [[Dutchtown Formation]], [[Glenwood Shale]], [[Joachim Dolomite]], and [[Wells Creek Formation]]
| overlies       = [[Beekmantown Dolomite]], [[Everton Formation]], [[Shakopee Dolomite]]
| thickness      =
| extent         = [[Arkansas]], [[Illinois]], [[Indiana]], [[Iowa]], [[Minnesota]], [[Missouri]], [[Wisconsin]] and [[West Virginia]]
| area           =
| map            =
| map_caption    =
}}{{Paleozoic Stratigraphy of the Upper Midwest}}The '''St. Peter Sandstone''' is an [[Ordovician]] [[geological formation]]. It belongs to the [[Chazyan]] stage of the Champlainian series in North American regional [[stratigraphy]], equivalent to the late [[Darriwilian]] global stage. This [[sandstone]] originated as a sheet of [[sand]] in clear, shallow water near the shore of a [[Paleozoic]] sea and consists of fine-to-medium-size, well-rounded [[quartz]] grains with frosted surfaces. The extent of the formation spans north–south from [[Minnesota]] to [[Arkansas]] and east–west from [[Illinois]] into [[Nebraska]] and [[South Dakota]]. The formation was named by [[David Dale Owen]] (1847)<ref>Owen, D.D., 1847, Preliminary report of the geological survey of Wisconsin and Iowa: U.S. Gen. Land Office Rept., 1847, p. 160-173.</ref> after the [[Minnesota River]], then known as the St. Peter River. The [[Type locality (geology)|type locality]] is at the confluence of the [[Mississippi River|Mississippi]] and Minnesota Rivers near [[Fort Snelling]], Minnesota.<ref>{{cite journal |last1=Stauffer |first1=C. R. |title=Type Paleozoic Sections in the Minnesota Valley |journal=The Journal of Geology |date=1934 |volume=42 |issue=4 |pages=337–357 |doi=10.1086/624173|bibcode=1934JG.....42..337S }}</ref> In eastern Missouri, the stone consists of quartz sand that is 99.44% silica.

==Outcrop==
In [[Minnesota]], the soft St. Peter Sandstone can be observed at the bluffs of the Mississippi River valley beneath a very thin layer of [[Glenwood Shale]] and a much thicker layer of [[Platteville limestone]].<ref name="TC">Mossler, J. and Benson, S., 1995, 1999, 2006, [https://web.archive.org/web/20170712030525/ftp://mgssun6.mngs.umn.edu/pub2/mnglance/.%2FMn_Fossils.pdf Fossil Collecting in the Twin Cities Area]. Minnesota at a Glance: Minnesota Geological Survey: University of Minnesota.</ref> Examples can be seen in the [[Mississippi Gorge Regional Park|Mississippi River Gorge]] and at [[Minnehaha Falls]] in [[Minneapolis]], the bluffs from downtown to [[Indian Mounds Park (Saint Paul, Minnesota)|Mounds Park]] in [[Saint Paul, Minnesota|Saint Paul]], and [[Minneopa State Park|Minneopa Falls]] near [[Mankato]]. In Illinois, [[Castle Rock State Park (Illinois)|Castle Rock]] is a large bluff of St. Peter Sandstone, and [[Starved Rock State Park]] and [[Matthiessen State Park]] feature numerous outcroppings and canyons.

==Commercial use==
St. Peter sandstone, also called "Ottawa Sand" in commercial applications, has a relatively uniform size and shape for each grain. It is used for the manufacture of [[glass]], for [[Media filter|filter]] and molding sand, and for [[abrasive]]s. Its purity is especially important to glassmakers. 

It is also important, as [[proppant]] otherwise known as frac sand in [[Petroleum|oil]] and [[Natural gas|gas]] [[Oil well|drilling]] &ndash; In [[Garnavillo, Iowa]], Northeast Iowa the Pattson sand company has been mining the sand and shipping it to the fracking areas of the US via rail cars.<ref>{{Cite web |title=Proppants |url=https://pattisoncompany.com/proppants |access-date=2025-05-19 |website=pattisoncompany.com}}</ref> loose sand pumped in a liquid mix under high pressure into a [[Oil well|well]] where the sand grains wedge into and hold open any fractures in the rock, enhancing the extraction of hydrocarbons. The uniform particle size also makes the sand useful for laboratory experiments.

==Mining locations==
St. Peter sandstone is or has been mined

*[[Arkansas]]: [[Guion, Arkansas]]
*[[Illinois]]: [[Ottawa, Illinois]], [[Sheridan, Illinois]], [[Wedron, Illinois]], [[Oregon, Illinois]], and [[Naplate, Illinois]]
*[[Minnesota]]: [[Kasota, Minnesota]] and [[Ottawa Township, Minnesota]]
*[[Missouri]]: [[Pacific, Missouri|Pacific]], [[Festus, Missouri|Festus]], [[Crystal City, Missouri|Crystal City]], [[Augusta, Missouri|Augusta]], and [[Pevely, Missouri|Pevely]]
*[[Garnavillo, Iowa]]

The [[Unimin]] Corporation is a large producer of commercial sand and operates surface mines in many of these locations.

==Notes==
{{Reflist}}

==References==
* Unklesbay, A.G; & Vineyard, Jerry D. (1992). Missouri Geology &ndash; Three Billion Years of Volcanoes, Seas, Sediments, and Erosion. University of Missouri Press. {{ISBN|0-8262-0836-3}}.
* [http://www.newton.dep.anl.gov/askasci/env99/env156.htm Void ratio of sand] Argonne National Laboratory, Division of Educational Program
* [https://web.archive.org/web/20061014161445/http://www.nps.gov/archive/miss/features/geology/geology.html Twin Cities Geology - Mississippi National River and Recreation Area]. National Park Service
* [http://www.wvgs.wvnet.edu/www/images/GenStratChartWV20151113.pdf Generalized Stratigraphic Column of West Virginia]

{{Chronostratigraphy of Illinois}}
{{Chronostratigraphy of Illinois}}
{{Chronostratigraphy of Indiana}}
{{Chronostratigraphy of Minnesota}}
{{Chronostratigraphy of Wisconsin}}
{{Stratigraphic column of West Virginia}}
{{Authority control}}

[[Category:Ordovician System of North America]]
[[Category:Sandstone formations of the United States]]
[[Category:Ordovician Arkansas]]
[[Category:Ordovician Illinois]]
[[Category:Ordovician Iowa]]
[[Category:Ordovician Minnesota]]
[[Category:Ordovician Missouri]]
[[Category:Ordovician South Dakota]]
[[Category:Ordovician Wisconsin]]
[[Category:Ordovician Nebraska]]